1. Field of the Invention
This invention is directed generally to waterbeds and particularly to waterbeds having an inner rigid frame member adapted to receive a cushioned cap or cover having rigid outer side walls.
2. State of the Art
During the past several years, there has been a substantial increase in interest and demand by the public for quality water beds. In response thereto, the waterbed industry has made important advances in making waterbeds more practical and more appealing to the public. This is evidenced by the substantial increase in issued patents in the waterbed field during the past decade. Some of the more important advances are reflected in the U.S. Pat. Nos. listed below:
3,736,604; 3,735,432; 4,015,299; & 4,062,077.
U.S. Pat. Nos. 3,736,604 and 3,735,432, for example, show generally the use of an inner frame having rigid side walls for containing the lateral forces generated by a bladder filled with water. The use of foam rubber to cover the frame is also disclosed in the above patents. In addition, U.S. Pat. No. 4,015,299 discloses the use of an inner frame for supporting a water filled bladder wherein the frame and bladder are surrounded by a dense foamy material for tempering unpleasant resonant wave characteristics. In U.S. Pat. No. 4,062,077, a rigid inner frame is described whereby the frame is adapted to receive a cushioned shell for covering the frame and the bladder held therein.
Although the above patents fairly well describe the advances recently made in the waterbed art, certain disadvantages still remain. In the use of a non-rigid cushioned shell, for example, there is a tendency for the cushioned side walls to separate near or at the bottom of the frame when a person is sitting or lying on the waterbed. In addition, this separation can cause migration of the insulating materials covering the bladder. Although this can be remedied by fastening a flexible cover (which normally encompasses the inner rigid frame member and the insulating material) to the frame's rigid side walls, this results in a cap or cover which for all practical purposes is permanently fixed to the inner rigid frame member and cannot be conveniently removed.
As previously stated, the lateral forces generated by a water filled bladder are held in check by the inner frame's rigid side walls. In order to prevent the side walls from breaking or bowing, relatively sturdy and costly materials must be used in constructing the frame's side walls. In addition, the end fastening means used in the construction of the frame must be selected with care to insure against separation and weakening of the frame's side walls.
One of the major disadvantages of most all waterbeds is, that in the event of a bladder leak, water can be released over the safety liner (inner rigid frame member) and onto the floor or be absorbed into the foam padding circumscribing and covering the bladder. If water is permitted to escape, floor and carpet damage may occur and the waterbed cannot be comfortably utilized until the water saturated foam rubber padding is completely dried.